As disclosed in Sestanj et al., J. Med. Chem., 1984, Vol. 27, pp. 255-256 (Sestanj et al. I) and U.S. Pat. Nos. 4,408,077 (Sestanj et al. II) and 4,439,617 (Sestanj et al. III), it is known that 6-alkoxy-5-trifluoromethyl-1-naphthoic acids are useful as pharmaceutical intermediates and that they can be prepared by a variety of techniques. It is also known that the syntheses of Sestanj et al. I and III can be modified by conducting the trifluoromethylation step as in Matsui et al., Chemistry Letters, 1981, pp. 1719-1720, and that particularly good results are obtained when N,N-dimethylacetamide is employed as the solvent in this step.
The known techniques of synthesizing these pharmaceutical intermediates have their relative advantages and disadvantages, but there is still a need for a synthesis that would be more attractive as a commercial process.